Estrogens mediate multiple complex physiological responses throughout the body. The responses are in turn mediated through the binding of estrogen to receptors. The classical receptors for steroids such as estrogen are soluble cytoplasmic/nuclear proteins that function as transcription factors. These receptors are known as estrogen receptor alpha and beta (two closely related proteins) and their various splice variants that mediate transcriptional activity as well as rapid cellular signaling. GPR30/GPER is a 7-transmembrane G protein-coupled receptor that has previously been suggested by Filardo et al., to mediate estrogen-dependent signal transduction. We have demonstrated that GPR30/GPER is largely an intracellular protein, found in the endoplasmic reticulum, that binds estrogen with high affinity (Kd˜6 nM) and mediates rapid cellular responses including calcium mobilization and phosphatidylinositol 3,4,5-trisphosphate production in the nucleus.
The current invention is in the field of molecular biology/pharmacology and provides compounds that modulate, particularly in a selective manner, the effects of GPR30/GPER and/or the classical estrogen receptors alpha and beta (ERα and ERβ). These compounds may function as agonists and/or antagonists of one or more of the disclosed estrogen receptors, particularly GPR30/GPER. Diseases which are mediated through one or more of these receptors include cancer (particularly breast, reproductive and other hormone-dependent cancers, leukemia, colon cancer, prostate cancer), reproductive (genito-urological) including endometritis, prostatitis, polycystic ovarian syndrome, bladder control, hormone-related disorders, hearing disorders, cardiovascular conditions including hot flashes and profuse sweating, hypertension, stroke, obesity, osteoporosis, hematologic diseases, vascular diseases or conditions such as venous thrombosis, atherosclerosis, among numerous others and disorders of the central and peripheral nervous system, including depression, insomnia, anxiety, neuropathy, multiple sclerosis, neurodegenerative disorders such as Parkinson's disease and Alzheimer's disease, as well as inflammatory bowel disease, Crohn's disease, coeliac (celiac) disease and related disorders of the intestine, fibrotic disease and/or conditions including pulmonary fibrosis, pulmonary hypertension, nephropathy (e.g. membranous nephropathy (MN), diabetic nephropathy and hypertensive nephropathy), glomerulonephritis (e.g. membranous glomerulonephritis and membranoproliferative glomerulonephritis (MPGN) such as rapidly progressive glomerulonephritis (RPGN)), interstitial nephritis, lupus nephritis, idiopathic nephrotic syndrome (INS) (e.g. minimal change nephrotic syndrome (MCNS) and focal segmental glomerulosclerosis (FSGS)), obstructive uropathy, polycystic kidney disease (e.g. Autosomal Dominant Polycystic Kidney Disease (ADPKD) and Autosomal Recessive Polycystic Kidney Disease (ARPKD)), liver fibrosis; cardiovascular: atherosclerosis, myocardial infarction, stroke, arterial hypertension, coronary artery disease, restenosis after balloon angioplasty, ischemia/reperfusion injury after myocardial or cerebral infarction, hypertrophic cardiomyopathy, heart failure, heart failure associated with aging (in particular diastolic dysfunction, also known as heart failure with preserved ejection fraction); renal disease states and/or conditions, including chronic kidney disease, glomerulosclerosis, proteinuric renal disease, hypertensive renal disease and nephropathy. Compounds according to the present invention may also be used as contraceptive agents to prevent or decrease the likelihood that a woman will become pregnant as a consequence of intercourse.
The invention relates to compounds that have been identified as being agonists or antagonists to one or more of these receptors and represent compounds that may be used to treat any one or more diseases or conditions mediated through these receptors. These compounds, due to their ability to bind selectively to GPR30/GPER and/or one or both of estrogen receptors (alpha and beta) are useful for the treatment or prevention of the diseases that are mediated through GPR30/GPER and/or one or both of the alpha and beta estrogen receptors.
Oxidative stress is a key determinant of cardiovascular aging, arterial hypertension, and heart failure. An essential source of reactive oxygen species (ROS) is the family of NADPH oxidase (Nox) enzymes. Nox1 is the primary inducible, superoxide-generating Nox subunit in vascular smooth muscle of large arteries with upregulated expression levels in hypertension. Sustained blood pressure increases in response to angiotensin II (Ang II), a potent vasoconstrictor peptide centrally involved in cardiovascular redox signaling, are blunted in Nox1-deficient mice. Conversely, overexpression of Nox1 exacerbates pressor responses to Ang II. Increased Nox1-derived oxidative stress has also been implicated in cardiac remodeling, myocardial fibrosis, and diastolic dysfunction. Therefore, targeting Nox1-dependent ROS production may be effective to inhibit pathological alterations in vascular tone and myocardial function.
Deletion of Gper, a 7-transmembrane G protein-coupled receptor also known to signal in response to estrogen, results in insulin resistance, glucose intolerance, obesity, and a pro-inflammatory state, increases vascular tone, whereas its activation induces vasodilation independent of sex. Furthermore, in a transgenic rat model of Ang II-dependent hypertension that is characterized by increased oxidative stress, selective GPER activation reduces vascular tone and blood pressure. Therefore, deletion of Gper would increase cardiovascular ROS production. Unexpectedly, eliminating constitutive GPER activity largely abolished Ang II-induced, Nox-mediated superoxide generation. This led us to investigate whether GPER might be involved in the regulation of Nox1 activity and in pathologies associated with increased oxidative stress in vivo, including arterial hypertension and cardiovascular aging.